Signal.



L. A. HAWKINS.

SIGNAL.

APPLICATION FILED 1330.29, 1908.

2 SHEETS-SHEET 1.

l-NVENTElRl LAUREN [:5 AHAW m N5 Patented Nov. 23, 1909.

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ATTY.

L. A. HAWKINS.

SIGNAL.

APPLICATION FILED 1) EU. 29, 190B.

Patented 510123, 1909.

2 SHEETS-SEEET 2.

WiTNEELE E-E'zri INVENTEIRI LALI REN EEAHAWKiNE! EPY AT TY.

UNETE STES PATENT FFTGEE,

LAURENCE A. HAWKINS, OF SCHENECTADY, NEW YORK, ASSIGNOB TO GENERAL ELECTRIC COlViPANY, A CORPORATION OF NEW YORK.

SIGNAL.

To all whomcit may concern:

Be it known that I, LAURENCE A. HAW- KINS, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Signals, of which the following is a. specification.

My invention relates to permissive block signals for electrically operated roads of the type in which a plurality of cars traveling in the same direction may be admitted to a block; each of the cars as it enters being counted by the signal mechanism, which is so arranged that the signals are not cleared until the last car has left the block. Such a system is disclosed in my prior application, No. 404,211, filed November 29, 1907.

The object of my present invention is to provide a simple and reliable form of counting mechanism adapted for use in a signal system of this type.

The counting mechanism frequently employed in signal systems of this type oomprises a ratchet-wheel and a pair of electromagnets provided with pawls for moving the mechanism step-by-step in opposite directions. These electromagnets are energized respectively when a car enters and leaves the block. A possibility of failure exists, unless special means are provided for guarding against it, because both countingin and counting-out magnets operate on the same ratchet-wheel; so that if the countingout magnet is energized by a car standing on the trolley contact connected with that magnet, the ratchet-wheel is locked by the magnet so that if a car enters the block at this time, the counting-in magnet is unable to move the ratchet so as to count the car in. iloreover, if the operating magnets, in addition to shifting the ratchetwheel, close electric contacts when energized, it is ordinarily necessary to provide means such as a dash-pot for retarding the return movement of the magnet cores in order that the contacts may remain closed a sufficient length of time to enable the lamps or other devices connected to the contact to respond to current, and with certain types of trolley contacts, in which the circuits of the magnets may be made and broken momentarily several times, due to the jumping of the trolley wheel in passing over the contact, it is especially necessary to employ means for retarding the return stroke of the cores of the magnet in Specification of Letters Patent.

Application filed December 29, 1908.

Patented Nov. 23, 1909. Serial No. 469,768.

order to preventa plurality of operations of the ratchet-wheel by the magnet, when it should be operated once only. When such retarding means are provided, the operation of the ratchet-wheel by the other magnet may be prevented by the retarding device of the first magnet.

The object of my invention is to render the operation of each magnet wholly independent of that of the other, so that it may produce its proper effect when energized, re gardless of whether the other magnet is en ergized or not.

My invention consists in providin a differential gear, one member of which controls the signal, and the other two members of which are operatively connected to the counting-in and counting-out magnets, respectively. Vith such a construction, the operation of each magnet is made independent of that of the other. The two magnets may operate simultaneously, without interference, when one car enters a block just as another is leaving it. Each of the two members of the gear connected to the magnets is moved, but the movements of these two members ofiset each other, as far as the third member controlling the signal is concerned, so that the third member remains unmoved, which is as it should be, since the number of cars in the block has not been changed.

My invention will best be understood by reference to the accompanying drawings, in which Figure 1 shows a front elevation, with the front of the casing removed, of a signal mechanism arranged in accordance with my invention; Fig. 2 shows a side elevation of the same; Fig. 3 shows a detail view of one of the ratchets; and Fig. at shows a cross sectional detail view of the differential gears.

In the drawings A represents a disk or target, which is displayed behind a window B in the casing C. This target is carried on a spindle a, which is operated by a crank (Z and a connecting rod D. The lower end of this connecting rod is secured to a lever E loose on the shaft F and controlled by a second lever G, which is fast to the shaft F. When the lever G is in the position shown, the connecting rod D is held raised. When the shaft F and lever G are moved one step in a clockwise direction, lever E is allowed to drop into engagement with the stop a, so

star-wheels L L.

that target A is rocked through ninety degrees and the indication changed. Contacts ll, may be placed on spindle a to control the lamps II, or other indicating apparatus. The shaft F, which is carried in suitable supports 7, carries near its center the memher I of a differential gear fast to the shaft. The other two members of the differential gear, J and J ,are loose on the shaft. These two members carry ratchetwheels K K and The ratchet-wheels K K are engaged respectively by the pawls k and 7;, which are actuated by the magnets M and M. Spring-actuated pawls Z and Z engage the star-wheels L and L, so as to limit the movement of each ratchet-wheel to one step or tooth when its actuating magnet is energized. The cores of the magnets may be connected to dash-pots m and m, which permit free upward movement of the cores, but retard their return movement. The pa vls 70 and is may carry contacts N N, adapted to engage stationary contacts a and a, when the magnets are engaged, to establish momentarily any indicating circuits which it may be desired to employ.

M is the counting-in magnet energized by each car entering the block. The first car entering the block, by energizing this magnet, shifts the ratchet K one tooth in a clockwise direction. This carries the member I of the differential gear in the same direction a distance equal to half that through which the ratchet K and gear member J move. This causes lever G to moveaway from lever E, allowing the latter to drop onto the stop 6. This produces the desired changes in the signal indications. A second car entering the block moves the lever G another step in the same direction. While ratchet K and gear member J are being shifted by magnet M, the other gear member J is held stationary by the star-wheel L and springpressed pawl Z. hen a car leaves the block, the magnet M is energized, shifting ratchet K in a counter-clockwise direction a distance of one tooth, and moving the gear member I half that distance in the same direction, thereby returning the lever Gr to ward lever E. Vhen the last car leaves the block, the lever G is returned to the position shown in Fig. 1, restoring the original signal indications.

It will be seen that the proper operation of the mechanism is not affected, if both magnets are simultaneously energized by cars entering and leaving the blocks at the same instant. Each ratchet-wheel is then moved by its magnet so that the two gear members J and J are both shifted, but in opposite directions. Gear member I and shaft F are consequently not shifted, so that the position of the signal controlling mechanism is not altered. This is the proper operation, since the number of cars in the block is not changed.

I do not desire to limit myself to the particular construction and arrangement of parts here shown, but aim in the appended claims to cover all modifications which are within the scope of my invention. 7

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a differential gear, a signal controlled by one member of said gear, a pair of electromagnets, and operative connections between the other two members of said gear and the two magnets respectively.

2. In combination, a differential gear, a signal controlled by one member of said gear, a pair of eleetromagnets, and operative connections between the other two members of said gear and the two magnets respectively, comprising step-by-step devices whereby one of said members is moved one step when either of said magnets is energized.

3. In combination, a differential gear, a signal controlled by one member of said gear, a ratchet-wheel carried by each of the other members of said gear, a pair of electromagnets, and a pan of pawls actuated by the electromagnets respectively and actu.

ating the ratchets respectively.

4. In combination, a differential gear, a signal controlled by one member of said gear, a ratchet-wheel carried by each of the other members of said gear, a pair of electro-magnets, a pair of pawls actuated by the electromagnets respectively and actuating the ratchets respectively, and means carried by each ratchet for limiting its movement to a predetermined amount when its actuating magnet is energized.

In witness whereof, I have hereunto set my hand this 28th day of December, 1908.

LAURENCE A. HAI/VKINS.

itnesses BENJAMIN B. HULL, HELEN ORFORD.

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